It has come to my attention that OIM has a severe lack of awareness for the awesome series that is known as the Touhou Project. And no, despite various indications that may suggest otherwise, Touhou is not an anime series. Touhou is actually a series of "shoot 'em up" video games, more specifically, vertical scrolling "bullet hell" games.
What makes the Touhou series especially great is that, like MLP, it has a rabid and extremely creative fanbase. In fact, when I initially got into MLP, Touhou was one of the first things that my mind used in order to explain the existence of such crazy and awesome fans. Fanmade art, music, animations, games, crossovers with just about anything you can imagine... You name it, it's all there.
Anyway, Touhou has a LOT of memes and is a HUGE part of remix culture on the internet... It's all too likely that you've seen a great deal of Touhou without even realizing it. So, without further ado...
This is a shadow art pony video based on a shadow art Touhou video, both of which use a fanmade Touhou song, Bad Apple. The original can be found here.
This is a pony video that features a remix of a remixed Touhou song... yep. The original remix can be found here, and the original original can be found here.
And because I am who I am, here's a video of Transformers: Prime with an English dub of Bad Apple, as performed by Cristina Vee. Proof that, like MLP, Touhou goes with EVERYTHING.
Want more Touhou? Check out the Know Your Meme page here.